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Whether to use lightened (21lb) flywheel on 83 280ZXT?


Guest jjohart

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Guest jjohart

I am wondering, first off, why every Z aftermarketer/maker did not see fit to making a lightened flywheel for the 280ZXT? Seems like every other Z variant can have one from stock...I saw a used, obviously shaved lightweight flywheel for sale, down to 21lbs (from 21), but I can't snare the seller for any negatives about its use in real world. His comment was he had one on a 74 which worked great...I'm pretty sure that car's equipment was worlds away from my 83 ZXT, no matter how old both cars may be.

Is there anyone who can tell me a reason NOT to do this with my Exedy racing/street-organic clutch, which I am holding off installing until I know whether I'll likely run into any nasty side effects..I've heard of "chatter", the car stalling out. If one should choose to answer this question, the bonus inquiry is as to why Nissan or aftermarket never offered l.w flywheels, intercoolers or underdrive pulleys for that matter.

Yes, I know..never put an underdrive pulley on a car with a lightened flywheel!~John

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I'm runnign Exedy organic disk and 400lb pressure plate. aka ACT :D with Fidanza 11lb flywheel (close J. :-D ) It has been holding ok. I have had chatters after slipping the clutch to built boost off line (Well, doh) but it's still in there and doesn't slip WOT.

 

Problem with 11 lb flywheel and 3.90 in turbo car is keeping the darn thing out of rev limiter. I've gained more than .7 sec by keeping it out of rev limiter. :D

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Guest jjohart

Well, it beats me...I tried all the usual Z aftermarketers, and my local installer also told me a 280ZXT (83) unit wasn't made/available..

As to weight, I would assume the 21 lb one I'm looking at isn't such a heavy weight loss as the 11lb ones being sold/mentioned.

I am still curious if there is some reason why my year and model, again an 83 ZXT 5 speed, would be a general no-no, at least from mainstream (i.e not race only suppliers). I was told by my clutch seller, Clutch City, that the stock 280ZXT's flywheel is "better"than any of the other Z flywheels, that it was custom designed for the turbo, and can hold a lot of pressure (?!)...so maybe this is the way I should look at it,no?

So is a four pound drop in flywheel weight from stock for a daily driver even worth it? My intent is to get away from the turbo lag as soon as possible!

Bye

John

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21lb is like stock I believe. And turbo flywheel is no different than any other 240mm flywheel.

 

Cool thing about Fidanza is it's both 225mm and 240mm so any clutch, turbo, N/A 2+2 will bolt up. A matter of fact, my clutch is for 300zx.

 

I really have almost no lag due with 3.90 and 11lb flywheel (I know it's not the best gear set) It's almost like driving an automatic with 3000rpm stall. :D

 

You got 3 inch downpipe? I know that helps. and smaller, shorter diameter IC pipes/

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Guest jjohart

So, if I wanted ZERO chatter for all reasonable NON-RACE, i.e street duty, what is the best weight for a flywheel...I'm sure your flywheel is great, as well as getting what you expected when starting off from a dead stop, aka at least a little chatter. My expectation is to keep it from chattering or making the revs bounce like a stag to the point that another owner might balk, thinking there's something wrong with it, or that I've raced it to death. Guess I'm looking for a bit of svelte, with a lot of stealth!

John-83 280ZXT

P.S., there ARE a lot of products which aren't contracted for sale on my model...I'm having to get my 3" exhaust system custom made, b/c the only run of "group buy" 280ZXT exhaust set ups are from Jeff B on Z car.com, and they don't even include the cat back pipe.

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Guest jjohart

BTW, what does 3000 rpm stall mean? Does that mean you're crusing on the highway at 65mph and it's reading 3000 rpm, and if you take your foot all the way off the pedal then the car stalls out?!! Sounds like a cruise control nightmare!

I stand waiting to be corrected!

John

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You need to consider why the factory kept the flywheel weight where it is.

 

A heavier flywheel is actually better for drag racing becuase it stores kinetic energy, and gets the car moving without bogging, which is never fun. Also if you have a large camshaft, it keeps the engine from chugging when driving at low rpms. And it is harder to stall.

 

Now you can lighten a factory one, best to take it out at the edge and work your way in.

 

If you road race a lot, the light flywheel would be the best way to go, for drag, I would stay with a standard weight one. Thats what I have.

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  • 2 weeks later...

Everyone always comes up with the heavier flywheel reply. Simply put, rotating mas is rotating mass. A hevier flywheel will take more torque from the engine to get it spinning, no question about that. What gets you down the track, and with good times is the engines ability to increase rpm, and the torque the engine produces.

Bogging, now that is a funny one. I can tell you @ 3000 rpm's my engine is not going to bog, no when you nail it an shove in 20 plus pounds of boost, your problem is not bogging, but rather keeping the car from doing a long burnout, that also is not good for racing, sure it looks good to spectators, but it ends up in slower times.

I took my stock flywheel off of my car and sold that boat anchor, and aslo you say the stock part is the best. I disagree with that myself, they are made from the cheapest material Nissan could find, all of it based on cost. The aluminum unit with the steel insert is a much better material for the clutch then the cheap material used in the stock part.

Go for it, call David at Mlvern Racing and get a part from him, install it, and if you think it was a bad choice then I will be more then happy to buy it from you as a spare for my car, thats if you dont destroy it or gall the bolt holes.

Regarding the clutch, the stock Nissan turbo clutch is better them most out there. I can tell you the center force part is not worth the powder to blow it away in a race application. I got 380 foot pounds of torque from it, and it puffed a little smoke from the bell housing and it was done, and when I took it on the freeway and tried to pass a car under high boost in 5th gear it slipped. I dont know about the ACT unit because I have never run one, but I do know one thing, if that unit is manufactured with standard disc material, it will not hold the power my car has, no question about that. And, there is an old saying, you want to play you got to pay, meaning to install a clutch that will hold the power, you are going to give up some of the street drivability, you cant get around it. Take a look at my page at the clutch disc, that part held 473 foot pounds of torque on the dyno and can hold more. I did lose some streetability as it doesnt like to slip much, but if it means I can realy put the power to it then I will just deal with it, and it isnt that bad anyway. :D

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Guest jjohart

Jeff P, writer of last post, I've been trying to reach you at two of your e mail addresses, but they're bouncing. Pls. e mail me or priv. message, I have some questions and business I keep typing over and over b/c they're bouncing everywhere else!!!

John H

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I run a spec stg.2, 240mm turbo clutch, kevlar disk and 450lb rated pressure plate, stock weight flywheel, its nice and hasnt slipped on me yet, and the pedal pressure is lighter than a valeo/factory nissan clutch!!

im sure a light flywheel is a good thing, pricy though. I would recommend the stage 2 to people though, many 5th gear romps and high speed freeway cruises with hard stabs into boost, and no slip.

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